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(No Model.) 2 Sheets-Sheet 1. G. MARSHALL.

STEAM BOILER.

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(No Model.) 2 Sheets-Sheet 2.

G. MARSHALL.

STEAM BOILER. No. 342,525. Patented May 25, 1886 N. PETERS. Phowuiho n mr. Nam D. C.

UNITED STATES PATENT ()FFICE.

GEORGE MARSHALL, OF DETROIT, MICHIGAN, ASSIGNOR TO ANDREIV J. PHELPS, OF SYRACUSE, NEW' YORK, AND ADALINE S. MARSHALL, OF DETROIT, MICHIGAN.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 342,525, dated May 25, 1886. Application filed March 525, 1886. Serial No. 196,501. (No model.)

To alt whom it may concern: A denotes the boiler shelhthesides of which I Be it known that I, GEORGE MARSHALL, of I compress to impart to said shell an oval or Detroit, in the county of \Vayne, in the State elliptic shapein cross-section, therebyincreasof Michigan, have invented new and useful ing the depth of the steam and water spaces 5 5 Improvements in Steam-Boilers, of which the and obtaining more room at the exterior of following, taken in connection with the acthe boiler. companying drawings, is a full, clear, and ex- In order to stiffen the flattened or broad aet description. j sides of the boiler-shell and maintain them in This invention relates to the class of steam shape,Iseeure to theinner sides thereof arched 60 1o boilers designated horizontal return flue braces c 0, arranged vertically, so as to bridge boilers, which have the fire-box inside of the said portions of the boiler, as shown in Fig. 4 boiler-shell with a water-space around the of the drawings. V fire-box, a combustion-chamber at the oppo- A is the head or front sheet of the boiler, site end of the boiler, a direct main flue eX- and Athe back sheet of the same. Both of 65 I 5 tending from the fire-box to the combustionsaid sheets are flanged outward and riveted chamber, and returnflues from the latter to to the inner side of the shell A in the usual the smoke box and stack at the front of the manner. The head A is provided with the boiler. fire-door opening I, which I extend to the The object of my invention is, first, to fabottom sheet of the firebox, and widen it 70 cilitate the construction of the internal parts thereat, so as to reach nearly or quite across 1, of the boiler and the attachment of the same the entire width of the fire-box, as shown at to the boiler-shell, secondly, to obtain better I, Fig. l of the drawings. access to the bottom of the fire-box for remov- B represents the fire-box, the front sheet of ing the ashes therefrom, and at the same time which I provide with an opening correspond 75 provide a larger opening for admission of air ing to the opening I I of the head A. The to the fire-box, and thus promote the combusfire-box sheet is flanged outward and abuts tion of fuel; thirdly, to impart to the boiler against the edge of an inward flange on the greatercapacity of containingwaterand steam head A around the aforesaid opening, and without increasing the Width of the boiler; over the joint between the said flanges Iplace 8o fonrthly, to protect the shell of the combnsa plain band, (I, and rivet the same to the tion-chamber from the destructive effects of flanges. This band presents asmooth surface the products of combustion, and to also augaround the fire-door opening and makes a ment the heating-surfaces of the boiler; and, more perfect finish thereat. The bottom porl fifthly, to form the junction of the fire-box tion of the enlarged opening I is formed by 8 3 5 with the front head of the boiler around the an extension of the bottom sheet of the firefire-door opening in a more perfect manner, box, which extension reaches across the front and so as to obviate projections around said water-space and laps over onto the flange of opening, and thus facilitate the removal of the head A, and is riveted directly thereto. ashes from the fire-bhx; and to attain these Consequently a continuous uniform surface is o objects my invention consists in the novel formed from the bottom of thefire-pot through construction and combination of parts, as the opening I, and therefore no obstructions hereinafter fully described, and specifically are presented to the scraping of the ashes out set forth in the claims. of the fire-box. Besides this, only one seam In the annexed drawings, Figure 1 is a front is formed and only one row of rivets required. 95

end View of my improved steam-boiler. Fig. 0 denotes the combustion-chamber, which 2 is a rear end View of the same. Fig. 3 is a communicates with the fire-box by the main vertical longitudinal section, and Fig. 4 is a flue D. Said combustion-chamber is formed vertical transverse section, of the boiler on line of the flue-sheet c, to which the main flue O and the return-fines a a are attached. The top 100 Similar letters of reference indicate correof the said flue-sheetI terminate below the wasponding parts. ter-line of the boiler, and the margin of the sheet I flange outward, as shown in Fig. 3 of the drawings. The back sheet,A, of the boiler is provided with an opening, f, similar to the fluesheet e in outline, but somewhat smaller in circumference. The sheet A is flanged outward around its said Opening, and to the flanges of this sheet and flue-sheet e is riveted the shell of the combustionchamber, which is gradually contracted and inclined at the top towards its rear end to lap onto the flange of the opening It will be observed that by this construction of the combustionchamber I obtain therein a crown-sheet which is submerged in the water of the boiler, and thus protected against injury from fire, and this crown-sheet adds heati ng-surface to the boiler, and by inclining said sheet, as shown, it becomes prolonged, and the heating-surface is thus increased. The attachment of the back sheet, A, to the boiler-shell I make by an in ward flange on said sheet, lapping onto the boiler-shell and riveted thereto, as shown in Fig. 3 of the drawings. Said back sheet, A, is thus set at the greatest possible distance from the flue-sheet e, and the combustionchamber 0 is accordingly enlarged.

In building my improved boiler I unite all the internal parts of the boiler before introducing and attaching them to the boiler-shelli. 6., I connect the fire-box B to the front head, A, and connect the combustionchamber G to the back sheet, A,and the main flue D to the fire-box B and flue-sheet e, and the returnflues a a to the said flue-sheet and head A, the head or end sheet, A, of the boiler being of proper size to fit to its place in the boiler, and flanged outward and perforated in the flanges for the reception of the rivets. I then introduce the before-described internal parts of the boiler into the boiler-shell and rivet the flanged head or end sheets, A A, to the said shell.

By the described construction I greatly facilitate the attachment of the component members of the boiler, and therefore reduce the cost of manufacture.

Having described my invention,whatIelain1 as new,and desire to secure by Letters Patent, 1s

1. The front head, II, and front sheet of the fire-box B, both provided with the fire-door opening I, formed with the widened extension I at the bottom of the fire-box, substantially as described and shown.

2. The combination of the boiler-head A, formed with an inward flange around the firedoor opening, the fire-box head formed with an outward flange around said opening and abutting against the edge of the flange of the head A, and the band d, placed over the joint of said flanges and riveted thereto, substantiall y as set forth and shown.

3. The boiler-shell of oval or elliptic shape in eross'section, and braces secured to the broad side thereof to stiffen and maintain the same in shape.

4:. The combination, with the boilershell of oval or elliptic form in cross-section, of arched braces secured vertically to the inner sides of the broad portions of said shell, substantially as described and shown.

5. In a steanrboiler, the combustion-chamher 0, formed of the outwardly-flanged fluesheet 0, terminating at its top below the water-line of the boiler, the back sheet, A, provided with the outwardly-flanged opening f of smaller circumference than the flue-sheet e, and the combustion-chamber shell gradually contracted in circumference and inclined rearward at the top, and riveted to the flanges of said flue-sheet and back sheet, substantially GEORGE MARSHALL.

\Vitnesses:

\VILLIAM MAY, J OHN W. SWEENEY. 

